Related interactions often occur at different regions of the brain and/or at different depths therein. The interrelationship of these interactions contains information that can provide insight into overall brain function, health, information processing, and the effects of pharmacological agents on the brain or other parts of the body. For example, in neuroscience, it is desirable to characterize the manner in which brain activity flows from one region to the next with cellular resolution. This is essential as information processing in the brain requires the collaborative and simultaneous work of multiple brain areas. In medicine, it is desirable to follow the simultaneous effect of new drugs on multiple parts of the body. Any pharmacological agent will have multiple and simultaneous effect on various parts of the body that need to be understood to fully appreciate its mode of action.
Consequently, in brain-imaging applications, it is often desirable to image disparate regions of the brain. Conventional microscopes are often employed for this service. A conventional microscope typically includes an imaging system that is upright and includes a large vertical objective, while offering three translational degrees of freedom for the relative positioning of the microscope and a sample.
Unfortunately, conventional microscopes are ill-suited for many brain imaging applications. First, the sample is normally constrained to lie flat on the microscope stage, while a brain is a three-dimensional object.
Second, the field-of-view of a conventional microscope is typically inversely proportional to the imaging resolution desired. As a result, high-resolution microscopy is normally limited to very small fields-of-view and is typically characterized by poor depth-of-field. As a result, it is difficult, if not impossible, to image different parts and/or depths of a brain at the same time. A conventional microscope, therefore, is incapable of providing information about coordinated brain activity at such scales.
Furthermore, using multiple microscopes to simultaneously image different regions of a brain is impractical due to the considerable bulk of a conventional microscope. This size constraint is particularly problematic when imaging small brains, such as a rodent or fly brain, as is commonly used in research.
In addition, the limited degrees-of-freedom of a typical microscope makes it illsuited for use during robotic brain surgery, which requires that an imaging system be carefully placed at any desired location and orientation with respect to a patient's brain.
As an alternative to conventional microscopes, light-based robotic therapy systems have been developed. Typically, the optical end effector is optically coupled to a light source via optical-fiber connections (e.g., through a catheter, etc.). Optically coupling the end effector and light source with an optical fiber limits the spectral bandwidth—among other light properties (e.g. polarization, pulse duration in case of ultrafast light sources)—available to the practitioner.